Boston-based BioDirection has raised a $4 million Series B round to back its point-of-care traumatic brain injury test Tbit. The financing is expected to enable the startup to finalize development and to start commercial planning for the test.

The Tbit system is based on nanowire technology that the company in-licensed from Nanosys that was originally generated by Harvard University. It incorporates a nanotech biosensor to detect and measure undisclosed protein biomarkers released from the brain after head trauma with test results available within 90 seconds. The test could enable earlier diagnosis of concussion, as well as help to reduce unnecessary head CT scans.

Provident Healthcare Capital, which is affiliated with healthcare investment bank Provident Healthcare Partners, participated in the financing alongside other undisclosed "globally recognized leaders in medical technology investment, some of whom have established associations with some of the largest hospital systems, providers and payers in healthcare," the company said in a statement.